A Phase II/III of Neoadjuvant FOLFOX with Selective Use of Combined Modality Chemoradiation versus Preoperative Combined Modality Chemoradiation for Locally Advanced Rectal Cancer Patients Undergoing Low Anterior Resection with Total Mesorectal Excision (PROSPECT)

[$] [Abbreviated - Closed] The purpose of this study is to compare the effects, both good and bad, of the standard treatment of chemotherapy and radiation to chemotherapy using a combination regimen known as FOLFOX, (the drugs 5-fluorouracil (5-FU), oxaliplatin and leucovorin) and selective use of the standard treatment, depending on response to the FOLFOX. The drugs in the FOLFOX regimen are all FDA (Food and Drug Administration) approved and have been used routinely since 2002 to treat patients with advanced colorectal cancer.